Metasurfaces, employed to simultaneously generate nanoprinting and holographic images, have been extensively explored recently. Among them, multi-wavelength multiplexing in a single metasurface is often accompanied by dispersion and crosstalk, which hinder the display of multicolor patterns. Here, we propose an efficient phase method to decouple the wavelength and realize a three-channel display operating at different wavelengths. Holographic images appear in the far field with the illumination of two different circularly polarized lights while a nanoprinting image is reconstructed by inserting an orthogonal optical path with the illumination of linear polarization light. The proposed metasurface is only composed of four types of unit cells, which significantly decreases the complexity of fabrication and improves the information capacity. Benefiting from its different decoding strategies and capability of multi-wavelength control, this approach may develop broad applications in information encryption, security, and color display.

No abstract

Multichannel metasurfaces are becoming a significant trend in the field of optical encryption due to their excellent manipulation of optical wavefronts. However, existent multichannel metasurfaces for optical encryption mostly implement only two channels in the near-field, or three channels by combining the near- and far-field. In this paper, we propose and simulate a three-channel metasurface that works entirely in the near-field and uses the polarization state of the incident light, left circularly polarized (LCP) light, right circularly polarized (RCP) light, and linearly polarized (LP) light as the security key. The metasurface consists of two types of nanostructures that work as a polarizer and a quarter-wave plate, providing an additional degree of freedom for encoding that enables independent near-field display at 633 nm wavelength incident light. The proposed three-channel metasurface has the advantages of high information density and high security, which will pave the way for multi-channel applications such as ultracompact displays, optical encryption, and information storage.